Variáveis determinantes da altura do salto de ataque do voleibol: uma análise cinemática e eletromiográfica

Abstract

In studies about the current volleyball game analysis, the spike is considered a decisive action to obtain point, victory in the game and the league title. Thus, the correct execution of the spike, can determine the success of the team and / or individual. To optimize the spike jump performance in volleyball there are several factors that must be taken into account. Due to the lack of research in this area, it became necessary to investigate the biomechanical variables which are decisive for the volleyball attack jump through correlation and regression of these variables. The study included eight healthy athletes. For acquisition of the kinematic variables were arranged three cameras, two Sony DCR-SR68 model (60 frames per second) and one Go- Pro (120 frames per second). Kinovea software was used for video analysis. To collect the EMG data we used a wireless electromyography (EMG) system (Shimmer), at a sampling rate of 1024 samples per second. The EMG data were collected through the Labview software and processed in Matlab. Participants attended the laboratory in just one visit. After signing the free and informed consent, we applied the PAR Q questionnaire. Then was performed the anthropometric characteristics of the volunteers (body weight and height) and familiarization with the attack jump was applied. Finally, the jump filming was done and was simultaneously collected the EMG data. Statistical analysis was performed using the tests: Multiple Correlation Pearson, Shapiro-Wilk, Durbin-Watson and F test. Was admitted a significance level of 5% (p> 0.05) for all analyzes. The results of this study point to a strong correlation between the variables "final horizontal velocity, horizontal average velocity, initial vertical velocity, average vertical velocity, horizontal average acceleration, EMG signal area of the left biceps femoris and right vastus lateralis" and "jump height". It was also presented an explanatory equation model of the jump height made up of the variables: Final airspeed, vertical speed and initial initial vertical acceleration. These correlations suggest the importance of the approach run well executed to improve the jump. From a practical point of view, this research may contribute to the direction of the team and individual training.